Rotary toothed cutter



March 26, 1935. .1. BAzzoNl ROTARY TOOTHED CUTTER Fiied sept. 29, 1932 Y Patented Mar. 26, 1935 nutren sirnrrs rsu-5,2590.

. FFiC RQTARY TOTHED CUTTER Lewis J. Bazzoni, Swampscott, Mass., assignor to United Shoe Machinery Corporation, Paterson, N l. .La corporation of New Jersey Application September 29, 1932', Serial No..635,395

s claims. 01.. isf-4.7.1.). j

This invention relates torotary cuttersv and is herein: illustrated as embcdiedin a. toothed-y lo' this' type: are equally capable of generating other outcurvedf. surfaces which. may be on work-pieces other than. wood heels. Nevertheless, the. invention is hereinafter set forth with. reference to that operation thef manufacture. of` wood. heels as spooling A spooling. operation, as. performed onV somey types of high/heels intended for Womens shoes., consists in rounding. the twov edges previously forme-d at the junctions of the breast andthe sides of. aheel. Not all high wood'. heelsy are spooled, and. so it is the practice to.Y shape them.

all, inthe iirst instance, so that they willi haveI sharplyl definededges at the junctions; above. mentioned. Those to be spooled. are subsequently roundedv as described, the roundedv surfaces, of. course, being outcurved. The spooling operation-.is commonly performed by aspecial machine.v

having two spool'ingcutters spaced apart to re-v ceiveea.. heel betweenthem. The cutters, onev well-known. type of spooling machine, are mount ed respectively on shafts that rotate opposite. directions about separate axes. Heretofore, it has. been considered necessary to use form cutters, that'is, cutters having incurved profiles and cuttingedges constituting counterparts ofl the outcurved surfaces to.` be generated thereby. Cutters of that type involve. manufacturing diiilv` culties with respect to'backing olif the teeth to provide cutting clearance, and with respect to sharpening the teeth so accurately as' to.- insure equal depth. of penetration by all the teeth.

Moreover, since the front faces ofthe teeth are the ones that require to be groundw when sharpening the cutting edges., the teeth grow thin and lose strength. in consequence of considerable` grinding. This eiect is aggravated by the necessity of grinding the high teet r more than the others to' takerthemV clown so that the cutting. burden be borne equally by all the teeth. Y Consequently, to avoid. these objectionable. causes and eiects, anl object of the present invention is to provide an improved cutter adapted to generate outcurved surfaces whether for heelspooling or forother purposes.

17o this endY and accordance with a feature.

of the invention, the,- illustrated Vrotary cutter is provided with skewed. peripherall cutting teeth arranged in a circular series concentric with the airisl ot rotation, each oftheteeth having top rake and a straight peripheral cutting edge of which 5.'

one end is circumferentially ahead of the other, whereby the effective profile of the cutter isl rendefedi equivalent tofthat of anincurved form cutter. In a cutter of this type no cutting edge lies in any plane inwhichfthe axis. of rotation lies. 10Y

As herein illustrated, the teeth of. the cutter are of. azform or proiile that permits economy of Inan-v ufacture, all of thermilled faces being at and capable oflv being.' generated in a Vnumber of steps equal tothe number of `teeth in the cutter. l5, Moreover, the circumferential skewing of the cut-J ting edgesnot only insures smooth cutting but n also avoids breakingout splinters as the teeth. leaveV a Workr-piece sincev each individual cut gradual-ly diminishes length to` a single point. 20.'A

before cutting edge leaves contact with theA y Work-piece. f v

Referring to the drawing,l

Fig. Irepresents an elevation.y 'of the front end of. a cutter embodying the present invention;

Fig. 2 represents a schematic side elevation of such. a cutterpartlv screened by a wood heel iny a position to be spooled thereby;

Fig. 3 is an elevation ofthe `rear end of theV cutter;

Fig. 4: is a front elevation of a portion of the cutterV including only one tooth thereof about to take a shavingV fromv a wood heel;

Fig. 5.4 is.: a view similar tol Fig. 4 except that the trailingend of the tooth has been advanced to the position of the leading end of the tooth in Fig. 4;

6 is: aschematic top-plan view correspondingl to Fig. 4- with respecttothe relationl between the cuttingedge of the tooth and thel heel;

Fig. '7 isl a top-plan view partly in section corresponding to Fig. 5 with respect to the relationbetween. the cuttingedgev and the heel;

Fig. 8 is a top-plan view of the cutter in out'- line, the effective profile of the periphery being represented by broken lines; K

Fig. 9 is a perspective front and side View of the cutter; Y

Fig. 10 is a perspective view of a'wood heel in which broken lines represent one of the two portions toA be trimmed off by what is known asr a spoolingoperation; and

Fig. 11 is a sectional view of the peripheral portions of three cutting disks'in gang relation suitable for milling the teeth of a cutter embodying the present invention.

The illustrated cutter is provided with a cylindric central bore 12, and with a plurality of uniform and integral peripheral teeth 14 arranged in a circular series concentric with the axis x of rotation. The bore 12 is intended to receive a Vshaft (not shown) to which the cutter will be afxed and by which it will be driven. Each tooth 14 is provided with a straight peripheral cutting edge 16 which, as shown best in Fig. 2, is oblique or skewed with respect to the axis of rotation whereby one end is placed circumferentially ahead of the other end, theintended direction of rotation being indicated by arrows in Figs. 1, 3, 4, and r and by the solid arrow in Fig. 2. The circiunferential lead of one end of each cutting edge with respect to the other end thereof is represented by the distance a-b in Figs. 1, 2,' and 4. The magnitude of this distance, the diameter of the cutter andthe axial dimension of the cutter govern the degree of' curvature of the surface tobe generated by the cutting edges. For purposes of explanation, it will be sufficient to state that the distance a-b'in the illustrated cutter is well suited to the requirement of a heel 18 of the type represented. i

In Figs. 4 and 5, the axis of rotation of the cutter isY represented by Vdots rc, and the dotted lines 20 represent the circle in which the trailing ends of the cutting edges lie. In Fig. 5 a dot-and-dash line 22 represents the circle in which the leadingl ends of the cutting edges lie'. *f Again referring to Fig. 4, it is to be observed that the leading end of the cutting edge 16 is at the level'of the axis :c and that' the top of the Y heel 18 is at the same level. `It may also be observed thatv the leading end of the cutting edge 16 is approximately tangent to the left-hand side of the heel. When a cutter and a heel of the types herein represented areset up in a spooling machine, they will occupy the relation represented in Fig. 4 during the early stages of a spooling operation. This relation is otherwise represented in plan view in Fig. 6 wherein the cutting edge 16 appears to be parallel to the axis sc, though in reality its rear end is at the level of line b (Figs. 1,y

2 and 4) while its forward end isy at the`level of line a. Now, assuming that the cutter is in rotation and that the tooth 14 represented in Fig. 4

' moves downwardly from the position represented in that gure tothe position represented in Fig. 5, the cutting edge 16 will penetrate the heel 18 and at the same time its angular relation to the heel will change from that represented in Fig. 6 to that represented in Fig. 7. This gradual angular variation causes the cutting edge to describe a hyperboloid of revolution and to generate an outcurved surface 24 on the heel. The cut progresses toward the breast of the heel from the pointof initial penetration nearer the back of the heel.

v A spooling machine such, for example, as that illustrated and described in United States YLetters .Patent No. 1,670,304, granted May 22, 1923 on application of J. W. Green comprises means for gradually raising a heel in process of being spooled; and means for gradually moving the heel backward as the operation progresses toward the base of the heel. In Fig. 10, the dotted lines represent the area to be trimmedvfrom one side of a heel by one of the spooling` cutters such as that herein illustrated, but vwhile this area is being trimmed on (see Fig. 7) the corresponding'l area at the opposite side of the heel will be simultaneously trimmed olf by a mated cutter of similar is not apparent when the cutter is stationary (see Fig. 2) but isapparent when it is in rotation. Thus, the curvature of the generated surfaces 24 of the heel will be counterparts of the curvature of the eective profiles 26 of the cutters.

VThe above-described skewed relation of the cutting edges 16 has the additional advantage of removing chips from wood heels without splitting or roughing the wood. In the manufacture of wood heels, it is a common practice, if not a universal practice, to arrange the fibres of the wood' so that they will extend from the breasts to the backs. This being so, it is apparent that the described Obliquity of the cutting edges 16 is most favorable to spooling heels without splitting the wood, since each cut progresses in the general direction of the length of the wood fibres but with a componentof progress toward the longitudinal median plane of the heel. Moreover, 'the skew or Obliquity of the cuttingedges with respect to their direction of travelvfacilitates the cutting action so that-each cutting edge enters and leaves the wood most favorably to the production of a smooth trimmed surface and most favorably to the avoidance of chipping or breaking out the wood at the points of emergence, since no two points in any cuttingedge enter or'emerge from the work-piece at the same time.

All the milling required to form the teeth of a cutter of the type herein shown may be performed with a milling cutter-of the form illustrated in Fig. 11. For economy such a milling cutter may conveniently be made in three sections or disks 30, 32 and 34 clamped in gang relationon a common arbor. If, now, the formof this composite milling cutter be compared with the tooth at the top center of Fig. 9 it will be apparent that the disk will generate 'the at back face 36, the disk 34 will generate the at front face 38of one tooth and the flat back face 40 of the tooth next ahead, and the disk 32 will vgenerate a flat outer face at the crown of the tooth.' This at face must be subsequently backed olf to provide cutting clearanceor relief, and may conveniently be altered incidentally to sharpening the tooth with the periphery 42 of a thin circular abrading disk (Fig.

3) arranged to rotate about an axis nearly if not exactly parallel to the edge being abraded. In Figures 1,13, V4, 5 and 9 the backed-off faces 15 are represented as having incurved or concave profiles the curvature of which corresponds to the circumferential curvature of the abrading disk. 1 In grinding'the faces 15 the cutter is secured in a holder (not shown) by which it is carried across theperiphery of the abrading disk with a compound motion one component of which is rectilinear and parallel to the line in which the cutting edge 16 is to be generated. The other component of such motion is angular motion about'an axis that coincides with the said line. The latter component counteracts the circumferential skewing of the cutting edges to provide uniform cutting clearance or relief at all points along the cutting edges.f See angle c in Figs. 4 and 5. In consequence of grinding the faces 15 CTI in the manner above described, these faces are twisted as represented in Figures 1, 4, 5 and 9.

y This method of grinding and an apparatus for putting it into practice form the subject-matter of U. S. Letters Patent No. 1,933,581, granted Nov. 7, 1933 on my related application led concurrently herewith.

Considering the profiles of the teeth, the front face 38 of each tooth is undercut to provide top rake. When, as shown, the front faces 38 are flat in addition to being skewed, the degree of rake or undercut is graduated, the maximum degree being at the trailing ends of the teeth, as represented by the angle d in Figures 3 and 5. This condition is most favorable to the avoidance of breaking out chips or splinters from wood heels, since the cutting angle of the teeth is thereby rendered most acute at the points last to leave contact with the work.

Having thusV described my invention, what I claim as new and desire to secure by Letters Patent of the United States isz- 1. A rotary cutter consisting of a single part provided with integral peripheral teeth skewed and arranged in a circular series concentric with the axis of rotation, each of said teeth havingtcp rake and a straight peripheral cutting edge one end of which is circumferentially ahead of the other end.

2. A rotary cutter provided with skewed peripheral teeth arranged in a circular series concentric with the axis of rotation, said teeth having each an outer face and an undercut front face intersecting each other and forming a straight peripheral cutting edge of which one end is circumferentially ahead of the other.

3. A rotary cutter provided with skewed peripheral teeth arranged in a circular series concentric with the axis of rotation, said teeth having each a twisted outer face and an undercut front face intersecting each other and forming a straight peripheral cutting edge of which one end is circumferentially ahead of the other.

4. A rotary cutter provided with skewed peripheral teeth arranged in a circular series concentric with the axis of rotation, said teeth having each an outer face at an angle of clearance and a flat undercut front face intersecting each other and forming a straight peripheral cutting edge of which one end is circumferentially ahead o f the other.

5. A rotary cutter provided with skewed peripheral teeth arranged in a circular series concentric with the axis of rotation, said teeth having each a flat front face of graduated rake and a twisted outer face intersecting each other and forming a straight peripheral cutting; edge of which one end is circumferentially ahead of. the other.

6. A rotary cutter provided with integral peripheral teeth skewed and arranged in a circular series concentric with the axis of rotation, said teeth having each a straight peripheral cuttingedge of which one end is circumferentially ahead of the other and having also a greater degree of top rake at its trailing end than at its leading end.

' LEWIS J. BAZZONI. 

